In order to shorten the time to vaporize fuel in a cylinder of an engine it is desirable to introduce fuel having a very fine particle size. In addition, to reduce the levels of emissions in an engine, especially a two cycle engine, it is desirous to inject fuel directly into the cylinder. U.S. Pat. No. 2,981,483 illustrates a low pressure fuel injector having a screw thread-like portion proximate its end. As the fuel flows through the helix of the thread it is rotated. The use of such a means to rotate or swirl the fuel does not yield a finely atomized spray and further such type of mechanism is expensive to manufacture.
It is an object of the present invention to inject fuel directly into a cylinder of an engine in a defined swirl or vortex pattern. Another object of the invention is to provide an injector that can inject fuel in a fully filled or partially filled conical swirl pattern. It is yet another object of the invention to provide an injector having a vortex chamber and to continually circulate fuel therein when the injector is closed to enhance the rapid formation of the conical swirl pattern. Still another object of the invention is to provide an injector capable of injecting a variety of different types of fuels, i.e., gas, oil, keroseen etc.
Accordingly, the invention comprises:
A high pressure vortex fuel injector comprising a hollow housing or body including a plurality of passages at least one of which is adapted to receive fuel through an inlet. A valve seat is secured to the housing and includes a metering orifice and a first surface disposed directly upstream of the metering orifice. The injector also includes means for guiding the piston into seating relationship with the valve seat to control the flow of fuel through the metering orifice and means for moving the piston relative to the valve seat. The injector further includes means upstream of the metering orifice for forming a swirl or vortex chamber in cooperation with the first surface such that upon removal of the piston from the valve seat, fuel flows out from the metering orifice in a conical spiral manner and means for receiving pressurized fuel and for causing the fuel to enter the vortex chamber in an angular manner. The vortex chamber is so constructed to angularly accelerate the fuel as it flows toward the metering orifice. The injector additionally includes means for permitting fuel to circulate about an electric coil thereof, thereby cooling same during instances when the metering orifice is closed. The injector further includes means for assisting in the rapid formation of a conical spray pattern upon the opening of the metering orifice. Such means includes a flow passage immediately upsteam of a valve seating surface. The flow passage is returned to a drain. By locating the flow passage proximate the bottom of the vortex chamber the swirling fuel therein can achieve a large angular velocity even when the metering orifice is closed. Upon opening of the metering orifice this rapdily swirling fuel is immediately ejected forming the spray pattern.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.